a pulse every 4 ticks (0.2 s) · 3 blocks

While the input is on, the output pulses every 4 ticks (0.2 s).

2 ticks (0.1 s) pulses · first after 2 ticks (0.1 s) · made of observer, sticky piston · fits in 2×1×3

5 versions, 4 to 20 ticks

a pulse every 4 ticks (0.2 s)Rapid fire while on3D view loading (or not available in this browser)

Every size 5

The best design for each size: pick one to see it.

size	blocks	numbers
4 ticks (0.2 s) (this page)	3 blocks	2 ticks (0.1 s) pulses · first after 2 ticks (0.1 s)
8 ticks (0.4 s)	12 blocks	4 ticks (0.2 s) pulses · first after 2 ticks (0.1 s)
12 ticks (0.6 s)	12 blocks	6 ticks (0.3 s) pulses · first after 2 ticks (0.1 s)
16 ticks (0.8 s)	12 blocks	4 to 8 ticks (0.2 s to 0.4 s) pulses · first after 2 ticks (0.1 s)
20 ticks (1 s)	12 blocks	10 ticks (0.5 s) pulses · first after 2 ticks (0.1 s)

Try it

Tap IN under the view to turn the input on, again to turn it off: turn it on and OUT keeps flashing red until you turn it off (the box marked OUT turns red while the output is on). Press play under the view to watch a demo on a loop; touch any other control to take over.

How this design does it: While the input is held on, two observers stare at each other and keep firing, a pulse every 4 ticks; it stops when the input goes off.

Build it

Download .litematic Download the design as text

The .litematic opens in Litematica (Minecraft 26.3): every block of the design in one region. The text file is the same build written as plain text, block by block.

Blocks used: observer sticky piston

Details: how it works, measurements and properties

In depth

While the input is on, the output pulses every 4 ticks (0.2 s) (5 pulses a second, each 2 ticks (0.1 s) long): a clock with an on switch, for rapid fire from dispensers and droppers while a lever is on.

The first pulse comes 2 ticks (0.1 s) after the input turns on. When the input turns off, no pulse starts more than 4 ticks (0.2 s) later.

How to try it

Press play under the view to watch the demo on a loop: the input held on for 20, 60 and then 200 ticks (10 s): the output pulses every 4 ticks (0.2 s) while it is on and stops after. The badge reads demo with the step it is on, and the same sequence is drawn as a timing diagram below. Touch any control to stop it and try the circuit yourself.

To try it: tap the IN button of the bar (or the cell tagged IN) to turn that input on or off (it powers the cell with a redstone block): turn the input on and the output pulses every 4 ticks (0.2 s) until you turn it off.

Inputs are tagged in lime; the output is tagged OUT: the redstone lamp in that cell (the view adds it to show the output) lights while the output is on (the output strip by the demo badge shows its last 40 game ticks, 2 seconds). Drag to look around, pinch or scroll to zoom, step one game tick at a time with the step button.

Inputs and output over time

The input follows this schedule (the 3D view's demo plays the same). Lime: an input is on; orange: the output is on (taller = a stronger signal, 1 to 15). Time runs left to right in game ticks (20 ticks = 1 s).

Swipe the diagram sideways: the whole sequence lasts 621 ticks (31.05 s).

Step by step (3 lines)

held 20 ticks (1 s): 6 pulses, first +2
held 60 ticks (3 s): 16 pulses, first +2
held 200 ticks (10 s): 51 pulses, first +2

Measurements

metric	value	what it means
P	4 ticks (0.2 s)	game ticks between two output pulses while the input is on
pulse	2 ticks (0.1 s)	the length of each output pulse
latency	2 ticks (0.1 s)	game ticks from the input turning on to the first output pulse
stop	4 ticks (0.2 s)	the latest an output pulse starts after the input turns off (0 or less: none after)

Notes from its designer

While the input is held on, two observers stare at each other and keep firing, a pulse every 4 ticks; it stops when the input goes off. Detail: 3 blocks: the input extends a sticky piston that pushes one observer face to face with the other (the chase), and retracting it breaks the pair apart

Properties

Study	Timers and pulse multipliers
Kind	Rapid fire while on (gated clock)
Blocks placed	3 (not counting the input levers or buttons and the lamp the view adds)
Box	2×1×3 (6 blocks of space)
Made of (the blocks that change state)	observer, sticky piston
Inputs / outputs	IN (repeater) / OUT
Flags	several versions of one mechanism
Design file	`pm-train-observers`

The design file

on GitHub

Design file (14 lines)

# Rapid fire while on: a pulse every 4 ticks (0.2 s) · 3 blocks
# https://vjeux.github.io/redstonepedia/circuits/pulsemult/pm-train-observers.html
name: pm-train-observers
circuit: pulse-train
port input: 3 1 3
port output: 1 1 0
palette:
  A minecraft:observer[facing=east,powered=false]
  B minecraft:observer[facing=west,powered=false]
  P minecraft:sticky_piston[extended=false,facing=north]
layer 1:
  ..A.
  ...B
  ...P